JPS5928478Y2 - alarm buzzer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a warning buzzer installed in a place exposed to muddy water, such as an automobile tire pressure warning device.

A tire pressure warning device is generally installed on a tire-mounted wheel 1 as shown in FIG.

In this figure, reference numeral 2 indicates a brake drum, and the wheel 1 is attached to the brake drum by attaching a wheel 10 and a road wheel 5 using bolts 3 protruding from the drum and nuts 4 screwed into the bolts.

6 is an air valve used to inject air into the tire, and an air pressure sensor 7 is attached to this air valve like a cap.
will be established.

Further, the bolt 3 and nut 4 are used to attach a case 8, which houses a dry battery, a wheel rotation detection switch, an alarm buzzer, and a buzzer drive circuit, which constitute a tire pressure alarm device together with an air pressure sensor 7, to the outside of the center of the road wheel 5. It is also used for

The air pressure sensor 7 is a pressure switch that constantly receives the tire internal pressure through the air valve 6 when installed as shown in the figure, and closes when the pressure falls below a set value. The signal is supplied to the buzzer drive circuit through the wheel rotation detection switch, which is closed during rotation, and the operation of this circuit energizes the alarm buzzer to notify a decrease in tire air pressure.

By the way, the above-mentioned alarm buzzer is usually constructed by supporting a diaphragm 12 provided with a piezoelectric element 11 in an end opening of a case 8 by an annular rubber member 13 having an H-shaped cross section, as shown at 10 in FIG. be.

The alarm buzzer 10 emits an alarm sound when the diaphragm 12 vibrates when a voltage is applied through the lead wire 14. Directivity is given by 16 and transmitted to the driver.

Therefore, the alarm buzzer 10 installed and used in the above-mentioned location can prevent muddy water from entering and adhering to the diaphragm 12 through the opening 16 when the vehicle is driving in the rain or on a snowy road. First, as shown at 17 in FIG. 2, mud was actually deposited around the annular member 13 due to the centrifugal force of 10 rotations of the wheel.

In this case, the movement of the diaphragm 12 may be restricted by the mud 17,
Due to reasons such as changes in the volume of the resonance chamber defined between the diaphragm 12 and the resonance cover 15, the sound pressure level inevitably decreases, and the alarm buzzer 10 may not be able to emit a sufficient amount of sound. In the worst case scenario, it becomes inoperable.

From these viewpoints, the present invention proposes an alarm buzzer that takes measures against muddy water by changing the shape of the diaphragm support member.

For this purpose, in the present invention, as shown in FIG. The member has a shape that expands so that the diameter becomes larger as it moves away from the plate 12, and furthermore, the inner diameter of the other end of the inner circumferential surface 13a of the member is smoothly connected to the end face opening edge 8a of the case 8.

In the alarm buzzer of the present invention in which the diaphragm support member 13 has such a shape, as shown at 17 in FIG.
It moves smoothly out of the case 8 along the outer twisted inner circumferential surface 13a of No. 3, and finally scatters outside the resonance chamber through the opening 16 of the resonance cover 15.

Therefore, there is no accumulation of mud as shown at 17 in Figure 2, and this ensures that the sound pressure level decreases due to accumulated mud and that the alarm buzzer becomes inoperable, which were problems with conventional alarm buzzers. It can be prevented.

In the illustrated preferred example, the inner circumferential surface 13a of the diaphragm support member 13 is a flat surface, but the inner circumferential surface 13a does not necessarily need to be a flat surface as long as it is twisted outwardly. It goes without saying that even if the surface is continuously curved, the effects of the present invention described above can be achieved.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of how to install the tire pressure warning device, Figure 2
The figure is a cutaway side view of a main part of a conventional warning buzzer used in the tire pressure warning device shown in FIG. 1, and FIG. 3 is a cutaway side view of a main part similar to FIG. 2 showing the warning buzzer of the present invention. 1...wheels, 2...brake drums,
3...Bolt, 4...Natsuto, 5...
... Road wheel 6 ... Air valve, 7
...Pneumatic sensor, 8...Case 9
, 14...Lead wire, 10...Alarm buzzer, 11...Piezoelectric element, 12...Vibration plate, 13...Vibration Plate support member, 13a...
... Inner peripheral surface of diaphragm support member, 15 ... Resonance cover 16 ... Resonance cover opening.

Claims (1)

[Scope of utility model registration request] In an alarm buzzer including a diaphragm supported through an elastic annular member in an end opening of a case, the inner circumferential surface of the annular member expands as it moves away from the diaphragm, and 1. An alarm buzzer characterized in that it is configured to expand outwardly and continue with an end opening.